An on-vehicle electrical junction box has various structures. For example, an electrical junction box 301 as shown in FIG. 7 includes: a frame 303; and a block 306 received in the frame 303. The frame 303 is provided with a double wall 330 as a waterproof structure (for example, see PTL 1).
The structure of the above electrical junction box 301 will be explained in more detail. The electrical junction box 301 includes: the above frame :303; the above block 306; a plurality of components such as a relay, a fuse, a bus bar, and an electric wire with a terminal (in FIG. 7, these components are omitted) attached to the block 306; an upper cover 304 attached to an upper end of the frame 303; and a lower cover 395 attached to a lower end of the frame 303. These frame 303, block 306, upper cover 304, and lower cover 305 are made of synthetic resin.
As described above, the frame 303 has the double wall 330 as the waterproof structure. The double wall 330 is composed of an outer wall 331 and an inner wall 332 having a gap therebetween. As shown by an arrow D in FIG. 7, the water entering from a mating portion between the frame 303 and the upper cover 304 is guided through a gap between the outer will 331 and the inner wall 332, and ejected outside from a not-shown drain hole on the lower cover 305.
The above block 306 has a plurality of component receiving sections to which the above components are respectively attached. Further, as shown in FIG. 7, in a component receiving section 360 arranged opposite to the double wall 330, a plurality of fuses are received in an upper end side, namely, the upper cover 304 side, and a plurality of electric wires with terminals and the bus bars are received in a lower end side, namely, the lower cover 305 side. Further, the terminals of the electric wires with terminals are received in the component receiving section 360, and the electric wires are guided out of the component receiving section 360.
Further, in a position where the double wall 330 and the component receiving section 360 are opposite to each other, a lower end 332b of the inner wall 332 is extended lower than a component insertion surface 361 disposed at the lower end of the component receiving section 360 so as to avoid soaking the fuses and the terminals of the electric wires in the water passing between the outer wall 331 and the inner wall 332. Here, the component insertion surface 361 disposed at the lower end of the component receiving section 360 is a surface where cavities for receiving the electric wires with terminals and the bus bars are opened.